The city’s Health Department released grim figures Thursday to demonstrate that mental illness is far more prevalent than most people realize — with one in five adult New Yorkers experiencing a “mental health disorder” in any given year.

The agency’s report also said that 8 percent of public high-school students reported attempting suicide.

To counter what they described as “devastating human costs of mental illness,” health officials said they’d begin rolling out new programs in coming weeks.

“Major depressive disorder is the single greatest source of disability in NYC,” the report said.

Health Department Deputy Commissioner Dr. Gary Belkin said the initiatives will involve several agencies, including his, the NYPD and the Department of Education.